The present invention relates generally to the construction of building shafts for enclosing elevators, stairways and the like, and more specifically, to an improved wallboard panel and an associated assembly for fabricating such shafts.
By code, shaft structures enclosing air return shafts, open shafts, stairway and elevator shafts and the like need to be fire retardant. Walls surrounding such shafts commonly separate the shafts from other rooms including corridors, restrooms and/or utility rooms. According to local building codes, such shafts typically have a fire rating of up to 2 hours to account for the fact that fires are often transmitted through such shafts from floor to floor of a building. In conventional modern building construction, such shafts are conventionally sheathed with gypsum wallboard of 1-inch thickness. It is customary to erect the shaftwalls from the surrounding rooms, without placing workers of equipment in the shafts themselves. Also, the shaftwall panels are held in place through a sliding relationship with surrounding metal studs or brackets. Conventionally, the panels are held in place in the brackets without fasteners. A suitable conventional shaftwall system is disclosed in U.S. Pat. No. 3,702,044 which is incorporated by reference. In the system disclosed in the '044 patent, the panels defining the shaftwall enclosure are 1-inch thick.
A manufacturing consideration of these panels is that standard wallboard is ½ inch thick, so the production line needs to be stopped and adjusted to manufacture the thicker 1-inch thick panels used in shaftwalls. Thus, a problem arises in scheduling production runs of special board, such as board which is twice as thick as conventional production panels. Accordingly, there is a need for an improved panel for shaftwall systems.